Internal-combustion engine.



No. 729,983. PATENTED JUNE 2. 1903;

H. F. WALLMANN'.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED MAY 31, 1899.

no MODEL, 2 snnms-snnnm'l,

PATENTED JUNE 2, 1903.

'2 sHEE'i'S-SHIIET 2.

H. F. WALLMANN. INTERNAL COMBUSTION ENGINE.

APiLIOATION FILED MAY a1, 1899.

HO MODEL.

THE NORRIS PETERS CO, PNOTOLITHQ. WASHINGTON, D C.

UNITED STATES PATENT Patented June 2, 1903.-

UFFIC HENNING FRIEDRICH WALLMANNK, or CHICAGO, ILLINOIS, ASSIGNOR TO THE WALLMANN ENGINE COMPANY, A CORPORATION OF ILLINOIS.

INTERNAL-COMBUSTION ENGINE.

$PECIFIGATION forming part of Letters Patent No. 729,983, dated June 2, 1903.

Application filed May 31,1399. Serial No. 718,904. (No model.)

To all whom it may concern:

Be it known that I, HENNING FRIEDRICH WALLMANN, a citizen of the United States, I

residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Internal- Oombustiou Engines, of which the foilowing is a specification. Y

My invention relates to Internal-combos tion engines of the two-cycle type, in which a charge of compressed air is mixed in suitable proportions with an inflammable gas or oil-vapor, ignited and expanded within the combustion-cylinder, and made to perform work against the piston at every outstroke of the latter. Engines-of this type have heretofore been frequently found somewhat difficult of successful and economical operation, owing chiefly to the difficulty experienced in effecting the thorough expulsion ofthe burned products of combustion without at thesame time Wastinga portion of theincoming charge or'to the liability of aconsiderable residuum of the burned products of combustion remaining in the cylinder and becoming mixed with, and thereby impairing the efficiency of, the incoming charge. generated in the cylinder-Walls of a two-cycle engine and the liability to premature explosion of the incoming: charge have also contributed to the difficulties experienced in the practical operation of this type of engine.

Among the several obj ectstherefore sought to be attained by the' improvements constituting my presentin'vention I may mention, first, increased efficiency and avoidance of premature explosions by thoroughly scavenging the combustion-cylinder bya blast of air at the end of each working stroke of the piston and before the fresh charge is admitted; second, preventionof the waste of fuel by mechanism which provides for the idle return of the fuel in the fuel-pump to the fuelreservoir while the scavenging operation is taking place in the combustion-cylinder and which permits the fuel: to be pumpedto the combustion-cylinder only after the scavenging operation has taken place and the ex haust-valve been closed third, the utilization of the maximum potential of each charge The excessive heat.

by the firing of the latter at such a point in the working stroke of the piston as I have found to-be most advantageous to secure the maximum expansive effect of the combustion;

of the Same, the fly-wheels in both figures being broken away.

, Similar letters refer to similarparts throughout bothviews.

L designates the base or bed plate of the engine, in which is journaled the crank-shaft S, carrying fly-wheels F and F' at either end thereof. Supported vertically on the bed plate L are the parallel frames N N, which carry at their upper ends the combustion-cylinder O and the air-pump cylinder A. Ar-

ranged tandem with and forming an extension of the air-pump cylinder A is the cylinder G of the fuel-pump, the plungers p of the air-pump and p of the fuel-pump being formed integral, as shown, or rigidly connected together, so as to move simultaneously under impulsesimpartedfrom the crankshaft S through crank s andconnecting-rod r. Within combustion-cylinder C is the working piston or plunger P, the latter connected to andoperating the crank-shaft S through the agency of connecting-rod r and crank s. It will be noticed that the two cranks s and s are not set in parallel'relation to. each other on the crank-shaft S, but about oneeighth of a revolution apart, the crank '8, connected to the Working piston P, being approximately fOrty-five degrees in advance-of the-crank s, which actuates the pump-plungersp and p, as best shown in dotted lines in Fig. 2. The purpose of this relative ar- IOO rangement of cranks will be disclosed later in the description of the operation of the engine.

Referring to the air-pump A, it will be noticed that the presence of the elongated plungerp, formed directly on the upper face of the air-pump pluugerp, creates an annular air-compression chamber within the cylinder A, to which air is admitted on the suctionstroke through the inlet-valve V and out of which it is forced on the compression-stroke through valve V and a mixer M into the combustion-cylinder C. The cylinder of the fuel-pump G is provided, preferably at its u pper end, with an inlet-valve c, normally held closed by a spring, but adapted to open on the suction-stroke and adapted to be positively held open during a portion of the discharge-stroke by means and for a purpose hereinafter described.

Reference-letter a represents a pipe which may connect with any main or pipe (not shown)containingordinaryilluminating-gas. Au inwardLv-opening check-valve '0 is 10- eated at a convenient point therein, and below this check-valve a rubber bag Bis interposed in the pipe a. At a point between the bag B and the pump-cylinder G the pipe 0: may conveniently be divided into two branches a (L2, the former containing an outwardly-opening check-valve v and the latter having an inwardly-opening check-valve 21 At a suitable point in the gas-inlet pipe a, preferably adjacent its union with the inletport a in the head of cylinder G, is introduced a short air-inlet pipe a containing an imrardly-opening check-valve '0 o is the discharge-valve of the fuel-pump, and b is a pipe leading therefrom to a chamber 0, formed in the head of the combustioncylinder and containing the mixer M.

Turning next to the combustion-cylinder C, it will be noted that the discharge-valve c of the fuel'pump forms, in effect, its fuelinlet valve, while the discharge-Valve 11- of the air-pump A forms, in eifect, its air-inlet valve.

11- designates the exhaust-valve of the combustion-cylinder. by a spring, as shown, but is positively opened at and during the proper period in the engines operation to effect the exhaust and scavenging of the combustion-cylinder by suitable mechanism, as hereinafter described.

Referring now to the mechanism for actuating and. controlling the exhaust-valve V of the combustion-cylinder and the inlet-valve v of the fuel-pump, R R designate a pair of,

standards mounted on top of the cylinders A and O. In the upper ends of these standards is suitably jonrnaled a horizontal rockershaft 61. Rigidly secured'on this rockershaft are two short arms or tappets d and d, the function of the former being to actuate the exhaust-valve V of the combustion-cylinder at the proper time, while the office of the latter is to engage and hold open the in- It is normally held closed 1 let-valve v of the fuel-pump against the action of its returning-spring at and during that period of time when the air-pump A is engaged in scavenging the combustioncylim der immediately following a working stroke. The rocker-shaft d is positively actuated from the crank-shafts of the engine through the agency of'a governor-controlled camdisk at on said crank-shaft, said cam-disk engaging and actuating one arm of a lever d pivoted to the bed-plate L, which lever conveys its rocking motion to an arm (1 fast on the end of the rocker-shaft cl, through the agency of a connecting-rod (1 which latter may reciprocate vertically through a bearing (1 secured laterally to the frame N.

At 61 is indicated an ordinary ball-governor mounted in the fly-wheel F and connected to the cam-disk d in such a wayas to vary the position of the latter laterally on the crank-shaft, according to the speed of the engine. It will be noticed that the disengaging edge of thecam (by which is meant that edge of the cam last to engage the lever cl) is formed on a line oblique to the line of the axis of the cam-disk, (see dotted line in Fig. 1,) so that the valves V and U will be held open a greater or less time, according to the position of the cam-disk d on the shaft S, and the speed of the engine regulated accordingly, as will be more fully explained in the description of the operation.

In the head of the comlmstion-cylinder and immediately below the mixer M is located the igniter I, which may be of any known and approved type and construction and which is not, therefore, shown and described in detail.

The mixer M may be of any approved con struction best adapted to the location shown, but is preferably like the mixer shown, described, and claimed in my pending application, filed December 17, 1898, Serial No. 699,377.

The operation of the engine is as follows: With the parts in the positions shown in the drawings the plungers p and p of the air and fuel pumps, respectively, have just reached the limit of their downward strokes. The cylinderA is filled with air previously drawn in through inlet-valve V, and thecylinder G is filled with fuel (preferably a non-ignitible mixture of ordinary illuminating-gas and air-as, for instance, equal parts of each) drawn in through check-valves v and o and inlet-valve 1), whose returning-spring is light enough to permit the valve to open on the suction-stroke of the pump. The piston P of the combustion -cylinder has completed a working stroke and has already started on its return stroke, its crank having traversed upwardly approximately forty-five degrees from the lower dead-center. (See Fig. 2.) At the completion of the downward or working stroke of piston P the cam d opened the exhaust-valve V through the mechanism already described and at or about the same time the tappet d was brought into engagement with the stem of fuel-inlet valve 1) to prevent the latter from closing at the com pletion ofthe suction-stroke. The burned products of combustion in cylinder are therefore already exhausting past the open exhaust-valve V3. As now the plunger P continues on its upward movement and pl ungersp and p commence theirsair compressed in cylinder A will be forced past valve V and mixerM into cylinder 0 and will scavenge the latter cylinder by blowing out the remaining burned products of combustion past the 7 open exhaust-valve V At the same time fuel compressed in cylinder G will simply be idly pressed back past the open inlet-valve 'o and check-valve '0 into the rubber bag B; but no fuel will pass to the combustion-cylinder until after the mechanism controlling valves 2; and V has permitted said valves to close.

This closing of valves 4; and V will occur sub-v stantially simultaneously after crank-shaft S has made'approximately one-fourth of a revolution fromits position, as shown in the draw-- ings-that is to say, pump-plungersp and p will then be about half-way up on their forcing strokes and working piston Pwill have completed nearly five-sixths of its return stroke. Duringthe remainder of the upward strokes of the three plungers 19,10, and P the first will be forcing air and the second fuel into cylinder C and the third, will be compressing the mixture in said cylinder, and owing to the fact that the working piston is one-eighth of a turn in advance of the'pumpplungers the latter will continue to supply, the combustible mixture to cylinder 0 even after working piston P has passed its upper dead-point and has made a considerable start on its downward stroke. At this point when p the plungers p and p havejust reached their upper dead-point and the working piston P is already moving rapidly on its downward or outward stroke the charge will be ignited and the pistonsdriven outwardly to the positionsshown, the. cylinders G and A drawing in new charges of fuel and air, respectively, whereupon the cycle of operations above described will be repeated.

In connection with the operation of the air and fuel pumps it is notedthat the expedient of holding open the inlet-valve of the fuel-pump during all or nearly all thescavenging operation elfects the simultaneous and equal compression of the air and fuel forced into the combustion-cylinder. 'This is important, because where the air and fuel are introduced in the combustion-cylinderat unequal pressures they will not mix properly, I

but that which is under the greatest compression will rush through or past the other and will enter the cylinder first. Such would be the case in this engine if the fuel in the fuelpump were put under compression from the very commencement of the compression-' stroke, while the scavenging operation is going on, instead of being allowed to idly return to the fuel-reservoir through the open inlet-valve until the exhaust-valve closes and compression of the air for the nei rt charg'e begins. In view of the fact that during and at the close of the scavenging operation the air incylinder A is under a slight compression it maybe found expedient in some cases to allow the fuel-inlet valve to close slightly in advance of the exhaust-valve of the com-' bustion-cylinder by arranging tappets d and v d slightly out of parallel relation on rockershaft'd' in order to insure the air and fuel entering the latter cylinder at equal pressures. This is a matter depending largely upon the size of the ports,strength of valvesprings, &c., and will be determined by experiment in each engine. By the expression substantially simultaneous,therefore, as used herein in reference to theclosing of valves 1) and V I mean such arelative operation of said valves as under all the given fuel-inlet valve o. If the engine gets to racing, the governor draws the cam-disk d outwardly, thereby prolonging the period of confact of the cam-face with the lever d and thus causing valves V and 'u to close later in the stroke of the plungers, whereby a smaller charge is admitted to the combustion-cylinder, and vice versa.

From the foregoing it will be seen that in an internal-combustion engine constructed and operating as hereinabove described all possibility of waste of fuel is avoided, because no fuel is admitted to the combustion-cylin- IIO der until after the latter has been exhausted, I

scavenged, and its exhaust-valve closed. The

fuel and air forming the components of each charge are supplied to the combustion-cylinder under equal pressures, wherebythey are more effectively mixedj Liability of prematureexplosion is avoided .by the thorough scavenging of the co rnbustion-cylinder before the next charge is admitted By the described arrangement of the working piston approximately one-eighth of a turn in advance of the -pum'p-plungers ignition of 'the charge, is cffected at a time when the working piston has 1 well passed its inner dead-point, is already rapidly moving outward, and is consequently inc-its most advantageous position mechanically to receive and transmit to. the crankshaft the full force of the expansion of the charge, and, finally, as a result of the fact that the charge from the instant of its ignition expands rapidly throughthe remaining'length of the piston-stroke its heat is less and is walls than where ignition takes place the in- 'more evenly distributed over thecylinder-r I stant the working piston has passed its upper dead-point and when its outward movement is very slow. The result of these improved features of construction and operation is an increase in both the efiiciency and economy of the two-cycle gas-engine.

Having thus'described my invention and illustrated the preferred embodiment thereof, what I claim, and desire to secure-by Letters Patent, is

1. In an internal-combustion engine, the combination with the crank-shaft and the air and fuel pumps arranged tandem, and having their plungers connected to the crank-shaft so as to reciprocate simultaneously, of the combustion-cylinder having its piston con nected to the crank-shaft'approximately fortyfive degrees in advance of the plungers of the air and fuel pumps, means for opening the exhaust-valve of the combustion-cylinder at the end of the Working stroke and for holding the same open through approximately half the compressing stroke of the air-pump, whereby the combustion-cylinder is exhausted and scavenged, and means for preventing the compression of fuel in the fuel-pu mp and its delivery to the combustion-cylinder until after the scavenging operation is completed, whereby air and fuel are supplied to the combustion-cylinder under substantially the same pressure, and the combustible mixture is compressed in the latter through the remainder of the instroke of the Working piston, all substantially as and for the purpose set forth.

2. In an internal-combustion engine, the combination With the crank-shaft and the air and fuel pumps arranged tandem, and having their plungers connected to the crank-shaft so as to reciprocate simultaneously, of the combustion-cylinder having its piston connected to the crank-shaft approximately forty-five degrees in advance of the plungers of the air and fuel pumps, means for opening the exhaust-valve of the combustion-cylinder at the end of the working stroke and for holding the same open through approximately'halt the compressing stroke of the air-pump, whereby the combustion-cylinder is exhausted and scavenged, means for preventing the compression of fuel in the fuel-pump and its delivery to the combustion-cylinder until after the scavenging operation is completed, whereby air and fuel are supplied to the combustion-cylinder under substantially the same pressure, and the combustible mixture is compressed in the latter through the remainder of the instroke of the Working piston, a mixer in the head of the combustion cylinder through which the components of the charge pass on entering said cylinder, and means for igniting the combustible charge when the plungers of the air and fuel pumps have reached theirinner dead-point and the working piston has performed approximately 011esixth of its outward stroke, all substantially as and for the purpose set forth.

3. In an internal-combustion engine, the combination with the crank-shaft, of the combustion-cylinder and an air-pump having their pistons operatively connected to the crank-shaft by means of cranks set at an acute angle to each other and the crank of theairpump following the crank of the combustioncylinder, an exhaust-valve for the combustion-cylinder and a valve between the com bustion cylinder and the airpump, both valves being open during a certain period of the instroke of both pistons for scavenging the combustion-cylinder by air from the airpump, and a fuel-pump provided with a positively-operated valve preventing the admission of fuel to the combustion-cylinder dur ing the period of scavenging, substantially as described.

4;. In an internal-combustion engine, the combination with the crank-shat t, of the combustion-cylinder and an air-pump having their pistons operatively connected to the crank-shaft by means of cranks set at an acute angle to each other and thecrank of the airpump following the crank of the combustioncylinder, a governor-controlled exhaust-valve for the combustion-cylinder and a valve between the combustion-cylinder and the airpump, both valves being open during a certain governor-determined period of the instroke of both pistonsfor scavenging the combustion-cylinder by air from the air-pump, andafuel-pump provided with a positively-operated governor-controlled valve preventing the admission of fuel to the combustion-cylinder during the period of scavenging, substantially as described.

HENNING FRIEDRICH WALLMANN.

Witnesses:

JOSEPHINE BEALE, SARAH GOLDBERG. 

